This invention relates to an improved flexible connector for a circuit breaker, and more particularly, to a flexible connector that provides a direct connection of each individual flexible connector to the vacuum interrupter stem.
Circuit breakers are useful for controlling and protecting electrical systems, apparatus and networks. A particular type of circuit breaker is a vacuum circuit interrupter apparatus which includes separable main contacts disposed in an insulated housing. Generally, one of the contacts is fixed relative to both the housing and to an external electrical conductor which is interconnected with the circuit to be controlled by the vacuum circuit interrupter. The other main contact is movable and usually comprises a cylindrical stem having the contact at one end thereof enclosed in a vacuum chamber and driving mechanism at the other end thereof external to the vacuum chamber.
Often the electrical interconnection between the circuit to be protected by the circuit interrupter and the movable contact is made on the cylindrical stem. Therefore, a need arises for channelling significant amounts of electrical current from a movable stem to a stationary electrical contact.
There have been several suggested prior art devices for transferring current from a movable contact to a fixed terminal. For example, U.S. Pat. Nos. 4,376,235 and 4,384,179 disclose a stiff flexible connector for a circuit breaker apparatus. A plurality of unitary, stiff, but flexible electrically conducting members are provided. The members are disposed in a horizontal position, but can move vertically due to a pleat in the member.
Commonly owned U.S. patent application Ser. No. 08/093,287 filed Jul. 16, 1993 discloses a flexible connector for connecting a movable contact of an electrical switch to a fixed electrical terminal. The flexible connector is a stack of flexible sheets of a conducting material and is constructed such that it can accommodate the movement of the movable contact.
In the above devices, the flexible connector includes a contact plate having tabs which maintain secure contact with the vacuum interrupter stem. The contact plates sandwich and are interposed between the flexible connectors making surface contact therewith. Thus, current is directed from the stem to the contact plate and then to the flexible connectors. There is no substantial direct contact between the flexible connectors and the stem.
What is needed, therefore, is a flexible connector that is directly in contact with the stem, and which in turn provides advantages over the currently available commercial flexible connectors.